The present invention relates to a semiconductor flow detector for detecting the flow rate and flowing direction of fluid.
To measure the flow of fluid, which plays a vital role in industries and everyday life, is employed in a wide area. Flow detectors of, for example, heat ray type and ultrasonic wave type are known to the art. However, the detectors of these types are bulky and complex in structure, leading to a high manufacturing cost. Also, these detectors are not suitable for mass production.
On the other hand, a semiconductor flow detector, which is small and permits measuring the flow rate at a low cost, is disclosed in, for example, "Monolithic Integrated Direction-Sensitive Flow Sensor" by Johan H. Huijsing et al; IEEE Transactions on Electron Devices, Vol. ED-29, No. 1, January 1982, and U.S. Pat. No. 3,992,940 to George E. Platzer, Jr. However, these detectors, which permit measuring only the flow rate of fluid, are incapable of measuring the flowing direction of fluid. In addition, a nonlinear relationship resides between the flow rate and the output voltage.
A detector capable of simultaneously measuring both the flow rate and flowing direction has not yet been developed except for the mechanical detector used for a weather survey. Under the circumstances, it is a matter of serious concern in this field to develop an inexpensive, small flow detector which readily permits measuring both the flow rate and flowing direction of fluid.